/*
    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU General Public
    License as published by the Free Software Foundation; either
    version 2 of the license, or (at your option) any later version.
*/

package org.gjt.jclasslib.structures.constants;

import org.gjt.jclasslib.structures.CPInfo;
import org.gjt.jclasslib.structures.InvalidByteCodeException;

import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;

/**
 * Base class for constant pool data structures which reference class members.
 *
 * @author <a href="mailto:jclasslib@ej-technologies.com">Ingo Kegel</a>
 * @version $Revision: 1.1 $ $Date: 2005/11/01 13:18:24 $
 */
public abstract class ConstantReference extends CPInfo {

    /**
     * Length of the constant pool data structure in bytes.
     */
    public static final int SIZE = 4;

    /**
     * <tt>class_index</tt> field.
     */
    protected int classIndex;
    /**
     * <tt>name_and_type_index</tt> field.
     */
    protected int nameAndTypeIndex;

    public String getVerbose() throws InvalidByteCodeException {

        ConstantNameAndTypeInfo nameAndType = getNameAndTypeInfo();

        return classFile.getConstantPoolEntryName(classIndex) + "." +
                classFile.getConstantPoolEntryName(nameAndType.getNameIndex());
    }

    /**
     * Get the index of the constant pool entry containing the
     * <tt>CONSTANT_Class_info</tt> of this entry.
     *
     * @return the index
     */
    public int getClassIndex() {
        return classIndex;
    }

    /**
     * Set the index of the constant pool entry containing the
     * <tt>CONSTANT_Class_info</tt> of this entry.
     *
     * @param classIndex the index
     */
    public void setClassIndex(int classIndex) {
        this.classIndex = classIndex;
    }

    /**
     * Get the index of the constant pool entry containing the
     * <tt>CONSTANT_NameAndType_info</tt> of this entry.
     *
     * @return the index
     */
    public int getNameAndTypeIndex() {
        return nameAndTypeIndex;
    }

    /**
     * Set the index of the constant pool entry containing the
     * <tt>CONSTANT_NameAndType_info</tt> of this entry.
     *
     * @param nameAndTypeIndex the index
     */
    public void setNameAndTypeIndex(int nameAndTypeIndex) {
        this.nameAndTypeIndex = nameAndTypeIndex;
    }

    /**
     * Get the class info for this reference.
     *
     * @return the class info.
     * @throws InvalidByteCodeException
     */
    public ConstantClassInfo getClassInfo() throws InvalidByteCodeException {
        return (ConstantClassInfo) getClassFile().getConstantPoolEntry(classIndex, ConstantClassInfo.class);
    }

    /**
     * Get the name and type info for this reference.
     *
     * @return the name and type info.
     * @throws InvalidByteCodeException
     */
    public ConstantNameAndTypeInfo getNameAndTypeInfo() throws InvalidByteCodeException {
        return (ConstantNameAndTypeInfo) classFile.getConstantPoolEntry(
                nameAndTypeIndex,
                ConstantNameAndTypeInfo.class);
    }

    public void read(DataInput in)
            throws InvalidByteCodeException, IOException {

        classIndex = in.readUnsignedShort();
        nameAndTypeIndex = in.readUnsignedShort();
    }

    public void write(DataOutput out)
            throws InvalidByteCodeException, IOException {

        out.writeShort(classIndex);
        out.writeShort(nameAndTypeIndex);
    }

    public boolean equals(Object object) {
        if (!(object instanceof ConstantReference)) {
            return false;
        }
        ConstantReference constantReference = (ConstantReference) object;
        return super.equals(object) &&
                constantReference.classIndex == classIndex &&
                constantReference.nameAndTypeIndex == nameAndTypeIndex;
    }

    public int hashCode() {
        return super.hashCode() ^ classIndex ^ nameAndTypeIndex;
    }

}
